Alloy



Patented Mar. 22, 1932 UNITED STATES" PATENT OFFICE BOHAINE G. WALT EN BEBG, OI" ROSELLE, HENRY EDWIN HOLBROOK, 01? IRVING'ION, AND BERT BRENNER, OF ELIZABETH, NEW JERSEY, ASSIGNORS TO THE E. A. WILSON COMPANY, OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY ALLOY No Drawing.

This invention relates to alloys and is concerned more particularly with novel alloys to be used primarily for such purposes as contact points in devices for maklng and 5 breaking electrical circuits.

In electrical devices of the type described, such as voltage regulators, the failure of the materials used for the contacts have frequently caused difliculties. These failures occur 1n a variety of ways as, for example, the contact points may fuse together or stick, the contact material may be lost due to mechanical wear or vaporization, or the surface of the contact element may become oxidized or 16 corroded so that upon closing, an abnormally high electrical resistance is introduced into the circuit due to the oxidation or corrosion. Also in some devices containing a pair of contact points, the contact material may be 20 transferred from one point to the other so that one contact point becomes pitted or eroded, while the other accumulates material or builds up. In extreme cases, this building up is localized and in time may become sufiicient to bridge the contact gap so that a normal separating movement of the points will not open the electrical circuit.

At the present time the contact points ordinarily used for electrical devices have been made of platinum or alloys of platinum with other metals, such as gold, iridium, osmium, palladium, rhodium and ruthenium. The contacts for an especially severe service have usually been made of platinum alloys, such as platinum with up to about 30% iridium or platinum, iridium, and osmium in equal amounts. In some alloys for these purposes, ruthenium has beenused in amounts of about 10 to 15% and it has been generally considered that in the proportions heretofore used iridium gave better results than ruthenium. We have discovered that alloys which give a superior performance as contact points can be produced by employing ruthenium in amounts much in excess of those heretofore employed. Also, we have found that in the range of amounts that we propose to use, ruthenium has advantages over iridium, which is contrary to what might have been 50 expected from the results obtained when Application filed March 6, 1931. Serial No. 520,707.

these metals are employed in lesser amounts.

In our new alloys we em loy ruthenium in amounts of at least 0 and preferably higher, ranging up to 90% with the remainder composed of one or more of the metals platnium, iridium and rhodium. We have found that an alloy containing ruthenium within the range specified, with the remainder made up of one'or more of the metals platinum, iridium and rhodium shows marked improvement over the ordinary platinum-iridium or platinum-iridium-osmium alloys in devices where the contact points must maintain a given position. There is considerably less transference of materials from one point to another, such erosion as occurs is substantially uniform over the contact surface, and there appears to be practically no change in the contacts resulting from mechanical deformation or Wear.

While improved results are obtained by employing ruthenium in amounts of 50% or more up to 90%, We have found that exceptionally good results are secured with an alloy which includes 70% by weight of ruthenium and 30% of rhodium, although the rhodium may be replaced either wholly or in part by platinum or iridiuim or a combination of the two.

The new alloys give better performance for contact purposes than those now used in the numerous respects mentioned. They have a higher melting point, and are of increased hardness and of greater stability. Also, there is less transfer of metal from one contact point to the other during service and less pitting occurs.

What we claim is:

1. An alloy containing between 50% and 90% ruthenium, and the remainder consisting of one or more of the metals platinum, iridium and rhodium.

2. An'alloy consisting of 50% to 90% of I 5. An allo consisting of 50% to 90% of ruthenium, a loyed with rhodium.

6. An alloy consisting of approximately 70% ruthenium and the remainder platinum. 5 7 An alloy consisting of approximately 70% ruthenium and the remainder iridium.

8. An alloy consisting of approximately 70% ruthenium and the remainder rhodium. 9. An alloy consisting of approximately 70% ruthenium and the remainder one or more of the metals platinum, iridium and rhodium.

In testimony whereof we afiix our signatures. ROMAINE G. WALTENBERG. HENRY EDWIN HOLBROOK. BERT BRENNER. v 

